1. Field of the Invention
The present invention relates to industrial plastics manufacturing processes and a new means of recycling excess trim. More specifically, the present invention pertains to a plastic-blow film extrusion trim reclaiming process that takes inline trim and reprocesses it into a reusable form, reducing material loss, excessive process cost and waste byproducts.
In the manufacture of plastic sheets in blown film extrusion processes, plastic material is extruded in the form of a bubble or tube and displaced away from the extruder necessary to cool, cure and form the sheet material. The bubble of material can be mechanically cut or shaped to form several different treatments, including rolled material, formed into a container or laid out and trimmed into sheets. During the trimming process, material is removed to form a desired shape, which creates a desired end product and a quantity of trimmed sections that are not readily usable. Generally it is desired to recycle this trim material in a reclaim process; however this is a secondary process that can be cost prohibitive and difficult to achieve.
Typical reclaim processes utilize an extrusion process to recycle the scrap trim material; however present devices for this task are erratic and not reliable. The present invention is therefore disclosed in order to address a clear need in the art for an inline reclaim process that can easily and reliably recycle lost trim from a plastic manufacturing process, wherein the trim is processed into uniform virgin pellets for reuse or formed into elongated bricks.
2. Description of the Prior Art
Several devices exist in the prior art that relate generally to process scrap material and specifically to processing scrap plastics into a reusable or sellable form. These devices have familiar design elements for the purposes of accepting waste trim from a third-party extrusion or plastics manufacturing process and for sizing, heating, cooling and collecting the transformed trim into its desired form. Generally, these processes involve a phase change or thermal load, along with a mechanical cutting process to repelletize the trim into a virgin material, readying it for introduction into an extrusion process that will reuse the material rather than discarding it.
The present invention relates to a new plastic trim reclaim device and process that processes waste scrap and plastic trim from a plastic manufacturing process and outputs formed sections of solid material or pelletized beads that are ready for reintroduction into the original plastic manufacturing process. The formed sections are known as “bricks” of plastic material, which can be utilized in the construction of structure, sold as virgin material or used as a convenient method of transport large quantities of plastic material in a condensed form. The pelletized form of the outputted plastic is ready for use in an extrusion process or similar plastics manufacturing process requiring pellets as a starting material. The pellets are fed into the process and generally heated prior to be extruded or formed.
The present invention describes a combination process that brings together two processes for the purposes of reclaiming scrap trim and transforming it into one of two optional forms: densified and sized composite bricks or pelletized bead material. Specifically, the present invention discloses a bricker and repelitizer that processes trimmed plastic material from another process and allows an operator to choose a desired output form. This offers plastics manufacturers, and specifically co-extrusion processes that ability to reclaim otherwise wasted material, which can safe time, material and money for the manufacturer. The process can also be utilized by an independent operator that processes the trim scrap on behalf of the manufacturer, whereafter the processed material may be sold or reused. In plastic-blown film extrusion processes, it is known that the equipment cannot directly re-utilize ground trim material and feed that trim directly back to the process material input section. Simple grinders do not produce the correct pelletized form required to begin the extrusion process, therefore such trim is generally discarded or sold, creating a loss of material and a process byproduct. Common practice is to ship out scrap to be repelitized with different verities of plastics; consequently, when the repelitized material is blended back into extruders, problems such as gels, discoloration, carbon buildup, and esthetic errors occur in the extruded output. To ensure the quality of the starting pellets and to reduce overall waste, the present invention utilizes an inline trim reclaim process that can be utilized to solve these known issues in the art of plastic extrusion processes and scrap material recovery thereof.
Several devices exist in the prior art that relate to plastics manufacturing and trim reclaim processes. The devices deemed most relevant after a review of patented and public disclosures are herein described to highlight the differentiating features of the present reclaim process. Specifically, U.S. Pat. No. 3,797,702 and U.S. Pat. No. 4,340,347 to Robertson disclose a scrap recovery and feed system for a plastic manufacturing system for the production of sheet, film, formed and molded objects, which recycles trimmed scrap material utilizing an inducer blower and forced air to blow scrap trimmings into a grinder. After the grinder, a separator separates the scrap from the air stream, whereafter the ground scrap falls into a feed hopper. The feed hopper is continuously filled with base and processed trim material to an extruding means. The Robertson devices relates to a process utilizing an adjustable vacuum-pressure airstream in which scrap flows along an open conduit to a grinder and then to a supply hopper of the processing system. The device is specific to the use of a pressurized air stream to move reclaimed trim back to the hopper starting point of the extrusion process. The present invention provides a means to pelletize the material for direct reuse. While also utilizing a forced air conveyance means, the present invention provides improved output and that which can be modified between composite bricks to virgin pellets.
U.S. Pat. No. 4,000,323 to Klaeyson describes a method for cooling and pelletizing thermoplastic material that includes compacting the material through a plurality of orifices. Flow rate of a gaseous steam is utilized as a heating source, which is regulated by a control circuit to maintain the heat utilized to transform the plastic material into a molten or semi-molten state. The regulation of temperature is critical to prevent overheating of the process that can lead to plastic agglomeration that can bind the compaction means and damage components. The Klaeyson device is primarily concerned with temperature regulation and an improved pelletizer, rather than a combined pelletizer and bricker for reclaiming lost plastic trim.
Finally, U.S. Pat. No. 4,467,969 to Godfrey discloses an improved method and apparatus for reclaiming film from an extrusion line. The system reclaims oriented and un-oriented film produced from a film process. The Godfrey device provides a trim reclaim process, but fails to disclose the novel structural aspects of the present invention, which provides a means to create virgin pellets for direct reuse, or composite bricks for alternative uses.
The present invention is a new and novel process that brings together several components to process extrusion trim material using a bricking process or a repelletizing process. One of two output types may be chosen for the purposes of reclaiming otherwise lost plastic trim. The present invention is a robust and operator-independent process that facilitates ready processing of trim material in an in-line configuration so as to conserve material and cost. The overall process is a new combination that is substantially divergent in design elements from the prior art; consequently it is clear that there is a need in the art for an improvement to existing devices. In this regard the instant invention substantially fulfills these needs.